This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


[Xen-devel] paged granttable entries

To: Patrick Colp <pjcolp@xxxxxxxxx>
Subject: [Xen-devel] paged granttable entries
From: Olaf Hering <olaf@xxxxxxxxx>
Date: Thu, 26 Aug 2010 14:13:55 +0200
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Thu, 26 Aug 2010 05:17:13 -0700
Dkim-signature: v=1; a=rsa-sha1; c=relaxed/relaxed; t=1282824842; l=750; s=domk; d=aepfle.de; h=Content-Type:MIME-Version:Subject:Cc:To:From:Date:X-RZG-CLASS-ID: X-RZG-AUTH; bh=rVbQ0DArQs2sY9eU2OJA2S7k9I0=; b=nfnHwHwp7cx3wsKV5vik1iYQwxGJm8DluWmZTc2megvDEBfvwzqR1pmRTAdUBKa9HWF i5iDmhIy2I9cg19EYgZVs5I8Djw7I/BeQ6Y+XuRF8eIbtvudPUwcwZjJQ6IKFP6PgNP20 NF+9/wu69rWPz10YI71o9BMXB5WmOI5Dthk=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.20 (2009-06-14)

after adding some debug to __gnttab_map_grant_ref(), I found the gfn
referenced by sha1->frame has p2m_type_t == p2m_ram_paged. As a result,
the following code gets into the 'iomem_access_permitted(rd, frame, frame)' 

Some naive approach to call p2m_mem_paging_populate() and return
GNTST_eagain lead to a deadlock in the guest. The guest reponds to keypresses,
xm destroy does not work.

How are paged out granttable entries supposed to come back when the
guest did not do the GNTTABOP_map_grant_ref hypercall yet? I tried to
skip gfn listed in the guests granttable in p2m_mem_paging_nominate, but
that doesnt appear to work because new pages can be added to the
granttable at anytime by the drivers.


Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>